Interruption of the transmission of Onchocerca volvulus in the Kashoya-Kitomi focus, western Uganda by long-term ivermectin treatment and elimination of the vector Simulium neavei by larviciding.

Uganda is the only country in sub-Saharan Africa whose onchocerciasis elimination programme extensively uses vector control and biannual treatment with ivermectin. The purpose of this study was to assess the impact of combined strategies on interrupting onchocerciasis transmission in the Kashoya-Kitomi focus. Mass Drug Administration annually (13 years) followed by biannual treatments (6 years) and ground larviciding (36 cycles in 3 years) with temephos (Abate®, EC500) against Simulium neavei were conducted. Routine fly catches were conducted for over seven years in six catching sites and freshwater crabs Potamonautes aloysiisabaudiae were examined for immature stages of Simulium neavei. Epidemiological assessments by skin snip were performed in 2004 and 2013. Collection of dry blood spots (DBS) from children <10 years for IgG4 antibodies analysis were done in 2010 and 2013. Treatment coverage with ivermectin improved with introduction of biannual treatment strategy. Microfilaria prevalence reduced from 85% in 1991 to 62% in 2004; and to only 0.5% in 2013. Crab infestation reduced from 59% in 2007 to 0% in 2013 following ground larviciding. Comparison of total fly catches before and after ground larviciding revealed a drop from 5334 flies in 2007 to 0 flies in 2009. Serological assays conducted among 1,362 children in 2010 revealed 11 positive cases (0.8%; 95% CI: 0.4%-1.2%). However, assessment conducted on 3246 children in 2013 revealed five positives, giving point prevalence of 0.15%; 95% CI: 0.02%-0.28%. Four of the five children subjected to O-150 PCR proved negative. The data show that transmission of onchocerciasis has been interrupted based on national and WHO Guidelines of 2012 and 2016, respectively.

The disappearance of onchocerciasis from the Itwara focus, western Uganda after elimination of the vector Simulium neavei and 19 years of annual ivermectin treatments.

The Itwara onchocerciasis focus is located around the Itwara forest reserve in western Uganda. In 1991, annual treatments with ivermectin started in the focus. They were supplemented in 1995 by the control of the vector Simulium neavei, which was subsequently eliminated from the focus. The impact of the two interventions on the disease was assessed in 2010 by nodule palpations, examinations of skin snips by microscopy and PCR, and Ov16 recombinant ELISA. There was no evidence of any microfilaria in 688 skin snips and only 2 (0.06%) of 3316 children examined for IgG4 were slightly above the arbitrary cut off of 40. A follow up of the same children 21 months later in 2012 confirmed that both were negative for diagnostic antigen Ov-16, skin snip microscopy and PCR. Based on the World Health Organization (WHO) elimination criteria of 2001 and the Uganda onchocerciasis certification guidelines, it was concluded that the disease has disappeared from the Itwara focus after 19 years of ivermectin treatments and the elimination of the vector around 2001. Ivermectin treatments were recommended to be halted.

Progress towards the elimination of onchocerciasis as a public-health problem in Uganda: opportunities, challenges and the way forward.

The national onchocerciasis-control programme in Uganda successfully eliminated Simulium neavei s.s. from the Itwara focus in 1997, by monthly ground spraying with larvicidal temophos (Abate). Since then, no vectors have been caught in the main Itwara focus or two secondary foci in the same area. After 4 years of intervention, S. neavei s.s. has also been nearly eliminated from the Mpamba-Nkusi focus, and the elimination of this vector from two more foci (West Nile and Wambabya-Rwamarongo) appears quite feasible. There are, however, four isolated foci in Uganda (Budongo, Kashoya-Kitomi, Mount Elgon and Kigezi-Bwindi) which are probably too large and inaccessible to make the elimination of S. neavei s.s. by ground spraying a realistic possibility. Encouragingly, >70% of Ugandans have received an annual dose of ivermectin for at least 10 years, and the national programme of community-directed treatment with ivermectin (CDTI) is thought to be progressing towards sustainability. Despite the good treatment coverages, however, many potential vectors are still found infected with Onchocerca volvulus and many Ugandans have O. volvulus in their skin. There is now evidence that adult O. volvulus can be eliminated, within a period of about 6 years, through semiannual treatment with ivermectin. Together, the isolated foci where vector elimination is not considered feasible have a human population of about 700,000, most of whom (595,000) are eligible to receive ivermectin treatment. The estimated cost of each treatment, via the Ugandan CDTI, is U.S.$0.78 if the salaries of the government-employed personnel and the working time lost by the volunteers who act as community-directed drug distributors (CDD) are taken into account. If these 'expenses' are ignored, however, the cost falls to just U.S.$0.17/treatment, and the total costs for the four isolated foci where vector control is not likely to be successful become about U.S.$101,150/year for annual treatment (for an indefinite period of time) or approximately U.S.$202,300/year for semi-annual treatment (for the 6 years needed to eliminate adult O. volvulus), which would be the more cost-effective option. With the necessary financial support and the continued free supply of ivermectin from Merck, the national onchocerciasis-control programme could eliminate human onchocerciasis from Uganda, through a combination of semi-annual treatment with ivermectin in the isolated foci where S. neavei s.s. elimination is not feasible, and vector elimination in all the other foci.

Community-directed interventions strategy enhances efficient and effective integration of health care delivery and development activities in rural disadvantaged communities of Uganda.

The community-directed interventions (CDI) strategy achieved a desired coverage of the ultimate treatment goal (UTG) of at least 90% with ivermectin distribution for onchocerciasis control, and filled the gap between the health care services and the communities. However, it was not clear how its primary actors--the community-directed health workers (CDHW) and community-directed health supervisors (CDHS)--would perform if they were given more responsibilities for other health and development activities within their communities. A total of 429 of 636 (67.5%) of the CDHWs who were involved in other health and development activities performed better than those who were involved only in ivermectin distribution, with a drop-out rate of 2.3%. A total of 467 of 864 (54.1%) of CDHSs who were involved in other health and development activities also maintained the desired level of performance. They facilitated updating of household registers (P<0.05), trained and supervised CDHWs, and educated community members about onchocerciasis control (P<0.001). Their drop-out rate was 2.6%. The study showed that the majority of those who dropped out had not been selected by their community members. Therefore, CDI strategy promoted integration of health and development activities with a high potential for sustainability.

Implementing community-directed treatment with ivermectin for the control of onchocerciasis in Uganda (1997-2000): an evaluation.

Over the period 1997-2000, an evaluation was made, in 10 districts of Uganda, of the onchocerciasis-control programme based on community-directed treatment with ivermectin (CDTI). This programme is supported by the Ministry of Health, the African Progamme for Onchocerciasis Control (APOC) and The Carter Center Global 2000 River Blindness Programme. The data analysed came from: (1) monthly and annual reports; (2) annual interviews, in randomly-selected communities in selected districts, with heads of household, community leaders and ivermectin distributors; (3) participatory evaluation meetings (PEM); (4) participant observation studies; and (5) key informants. The percentage of treated communities in the 10 study districts achieving satisfactory treatment coverage [i.e. > or = 90% of the annual treatment objective (ATO)] rose from 46.0 in 1997 to 86.8 in 2000. This improvement was largely attributable to the adoption of collective CDTI decision-making by community members, avoidance of paving monetary incentives to the ivermectin distributors, and the satisfaction with the programme of those who had been treated. Coverage improved as the numbers of community members who were involved in choosing the method of distribution and in selecting their own community-directed health workers (CDHW) increased. Health education was also critical in improving individual members' involvement in decision-making, and in mobilizing other community members to take part in CDTI. Involvement of kinship groups, as well as educated community members as supervisors of CDHW, also helped to increase coverage. In a regression model, satisfaction with the programme was revealed as a significant predictor of the achievement of the target coverage (P<0.001). Cost per person, as an indicator for sustainability, varied with the size of the population under treatment, from at least U.S. $0.40 when the district ATO was <15,000 people, to U.S. $0.26 with an ATO of 15,000-40,000 and less than U.S. $0.10 when the district ATO exceeded 40,000 people. These results cast doubt on the validity of the current APOC indicator for sustainability, of a cost of no more than U.S. $0.20/person for all CDTI projects, whatever the size of the population to be treated. Although some women were involved in decision-making, their current involvement as supervisors or CDHW was minimal. Most of the present data were obtained through monitoring and operational-research activities that have been carried out, in an integrated fashion, within the Ugandan CDTI programme since its launch. It is recommended that assessment, monitoring and evaluation be widely used within all CDTI efforts. Operational research should remain focused and appropriate and directly involve the personnel who are executing the programme.

Involvement of women in community-directed treatment with ivermectin for the control of onchocerciasis in Rukungiri district, Uganda: a knowledge, attitude and practice study.

A study of knowledge, attitudes and practice was carried out in the Rukungiri district of Uganda, in order to investigate the involvement of women in community-directed treatment with ivermectin (CDTI), for the control of onchocerciasis. The data analysed came from interviews with 260 adult women (one from each of 260 randomly-selected households in 20 onchocerciasis-endemic communities), community informants, and participatory evaluation meetings (PEM) in eight communities. The women who had been treated with ivermectin in 1999 generally had more knowledge of the benefits of taking ivermectin, were more likely to have attended the relevant health-education sessions and were more involved in community decisions on the method of ivermectin distribution than the women who had not received ivermectin in that year. There were fewer female community-directed health workers (CDHW) than male CDHW in the communities investigated. The reasons for not attending health-education sessions, not participating in community meetings concerning the CDTI, and the reluctance of some women to serve as CDHW were investigated. The most common reasons given were domestic chores, a reluctance to express their views in meetings outside their own kinship group, suspicions that other women might take advantage of them, and a lack of interest. Most of the women interviewed (as well as other community members) felt that there were relatively few women CDHW. The women attributed this to a lack of interaction and trust amongst themselves, which resulted in more men than women being selected as CDHW. The rest of the community members were not against women working as CDHW. It is recommended that communities be encouraged to select women to serve as CDHW in the CDTI, and that the performances of male and female CDHW be compared.